Focused Electron Beam Induced Deposition of Gold and Rhodium
- PDF / 3,000,997 Bytes
- 7 Pages / 396 x 630 pts Page_size
- 77 Downloads / 216 Views
P. HOFFMANN', I. UTKE, F. CICOIRA* *Institute of Applied Optics, Swiss Federal Institute of Technology Lausanne, CH-1015 Lausanne-EPFL, Switzerland, [email protected] B. DWIR**, K. LEIFER**, E. KAPON** **Institute of Micro- and Optoelectronics, Swiss Federal Institute of Technology Lausanne, CH-1015 Lausanne-EPFL, Switzerland P. DOPPELT*** ***ESPCI-CNRS, 10 rue Vauquelin, 75231 Paris Cedex 05, France
ABSTRACT Electron beam induced deposition with two noble metal precursors (Rhodium and Gold) having the same halogeno and trifluorophosphine ligands is presented. The deposit geometry of lines and freestanding bridges is discussed with respect to electron energy, beam shape, and backscattered electron distribution. Electron beam heating effects are estimated to be negligible in our deposition conditions. Using PF 3AuCl, lines of percolating gold grains were deposited with electrical resistivities as low as 22p•g2cm at room temperature (Au: 2.2[tg0cm). Auger electron analysis shows about 60at% Rh in deposits obtained with [RhCI(PF 3)212 , however the resistivity of 102cm is high compared to 4.5gjacm of pure Rh.
INTRODUCTION Focused electron-beam induced deposition (EBID) offers high flexibility compared to classical lithographic microelectronics processing. Deposition of metals and insulators of high aspect ratio columnar structures, air-bridges and other 3D features is possible. Limiting for most applications is the low deposit purity resulting in low electrical conductivity and low average grain density of deposited metal structures. Increasing the substrate temperature during EBID with Me 2Au-(tfa) as precursor increased the metal/carbon ratio to 22at% [1]. The high carbon content in the deposits results from both the oil vapors in the electron microscope pumping system and to a higher extend from the carbon rich precursor ligands. For improvement the addition of efficient carbon etching partner gases in combination with noble metal precursors was proposed: adding oxygen into the deposition chamber together with Me2 Au-(tfa) as gold precursor resulted in 50at% Au [2]. The carbon free precursor WF 6 tested for EBID resulted in almost pure W [3]. In this article we present EBID of Rh- and Au-rich structures from carbon and oxygen free trifluorophosphine chloro complexes without substrate heating nor adding reactive gases.
171 Mat. Res. Soc. Symp. Proc. Vol. 624 ©2000 Materials Research Society
EXPERIMENTAL Deposition Our EBID system is based on a scanning electron microscope (SEM) Cambridge S100 with tungsten filament, operating in steps between 3kV and 25kV. For deposition the electron beam is controlled by a Nabity NPGS lithography software running on a PC. Dwell times and point-topoint distances can be varied between l~ts to Is and 5nm to 5[in, respectively. Horizontal lines were deposited as single slow scan with 10nm point-to-point distance and a dwell time of Is. Further reduction of the scan speed results in three-dimensional tip deposition with different inclination angles (vertical if scan speed is
Data Loading...
